I guess I wasn't clear, I would have that 01 250 shock mounted up so fast it would make your head swim. The 250 shock has a heavier shaft than the 500, plus as a bonus it has high and low compression. If it was just laying around I would use it even if you have to have it revalved, do the 250 shock. Unless your going to be doing some hardcore racing the 250 shock will be fine, you may need to use the 500 spring. I would think your kawi dealer will change oil and recharge for $50-75, If it needs a new seal thats about another $50-60. usually if they have been ridden with no gas pressure the seals will fail and your oil will be lost. You can tell if oil is lost by removing the spring, stroke the shaft back and forth there should be a constant resistenance, if you get to a point where the shaft moves easily you probably need oil, and frankly if it hasn't been done, do it, you won't believe how much better your bike rides.